We have developed a field research methodology to identify and gain access to youthful multiple drug users in the natural setting. We have completed the study of a large drug use and distribution site in the south Chicago suburbs and by the end of the 02 year will have completed the data collection phase of ongoing studies at an urban north-side site. Our ultimate goal is to devise a field team intervention-referral model aimed at decreasing damaging patterns of illicit drug use in youthful populations. To accomplish this goal we are requesting a third year renewal. First, we will complete analysis of the social organization, epidemiologic drug use trends, and the broad range of service needs of users at the urban site. Secondly, we will study interaction between the drug using groups and their host community to determine what factors reinforce and discourage drug use, availability, and the congregation of users and dealers at specific sites. Thirdly, we will compare the range and degree of psychopathology among these youth with that of youthful drug users already in treatment and with "normal" adolescents and determine the selection factors which lead to some individuals being placed in residential drug treatment programs. Finally, we will assess the service resources needed and available in the target community, pilot test a fieldwork intervention-referral strategy, determine factors which make for successful referrals, design outcome measures, and develop a research proposal for a rigorous evaluation of the efficacy of the field intervention method.